The present invention relates to wind turbine sensors.
Modern wind turbines include a number of sensors for monitoring external parameters such as wind speed and wind direction, and internal parameters such as vibration and strain affecting the wind turbine blades and other components. Information from these sensors is used for controlling the wind turbine and for monitoring the health of the wind turbine components.
Many wind turbine sensors are made from metallic components. However, as wind turbines are very tall structures and these sensors tend to be located externally at the top of the tower or on the rotating blades, they are susceptible to lightning strikes. To counter this problem a sensor made entirely from non-metallic components has been proposed in WO2011/095170. Alternatively, the sensors may comprise galvanic insulation to reduce the risk of lightning strikes.
Another problem affecting wind turbine sensors is ice accretion. In cold conditions ice may accumulate on the wind turbine blades and other parts of the wind turbine. If this ice covers the sensors it may prevent the sensors from operating effectively.
Against this background, the present invention aims to provide an improved sensor system that does not suffer from the problems described above.